Cancer Research Institute, Southern Medical University, Guangzhou, 510515, China.
Biomacromolecules. 2010 Dec 13;11(12):3531-8. doi: 10.1021/bm101013s. Epub 2010 Nov 18.
To enhance site-specific intracellular delivery against folate receptor, heparin-PEG-folate (H-PEG-F) containing succinylated-heparin conjugated with folate via PEG 1000/3000 spacers has been prepared. Due to covalent strategy, H-PEG-F displays amphiphilic property, which is capable of entrapping a hydrophobic agent, like taxol, to form heparin-PEG-folate-taxol nanoparticles (H-PEG-F-T NPs) in aqueous solution. Hydrophobic agents can be entrapped within the core, while the H-PEG-F conjugates can stabilize the nanoparticles with exposing folate moieties on the surface. The structure of carrier and naoparticles has been characterized by(1)H NMR, and the content of folate and taxol has been quantitatively analyzed by UV method. The morphology and size of H-PEG-F-T NPs have been measured by field emission scanning electron microscopy (FESEM) and dynamic lighting scatter (DLS). All the NPs are in spherical shape and the sizes are less than 200 nm. The sizes of the NPs increases with increasing PEG segment length. By employing the flow cytomery method, the extent of cellular uptake has been comparatively evaluated under various conditions. The results of cellular uptake demonstrate that the cellular uptake of the carrier and the NPs is exceedingly higher for KB-3-1 cells (folate receptor overexpressing cell line) than for A549 cells (folate receptor deficiency cell line); H-PEG-F-T NPs show far greater extent of cellular uptake than that of H-PEG-F conjugates against A549 cells; when the content of folate is fixed at the same value, the extent of cellular uptake for the carrier and NPs ascends with the increase of PEG chain length against KB-3-1 cells. It suggests folate-receptor-mediated endocytosis and formation of nanoparticle and spacer length are considered to coaffect the cellular uptake efficiency of H-PEG-F-T NPs and H-PEG-F conjugates. Flow cytometry analysis depicts that KB-3-1 cells treated with H-PEG-F-T are arrested in the G(2)/M phase of the cell cycle, which states the similar inhibition mechanism as taxol. The strategy based on the formation of H-PEG-F-T NPs could be potentially applied for cancer cell targeted delivery of various therapeutic agents.
为了增强针对叶酸受体的细胞内递药作用，通过 PEG 1000/3000 间隔臂将接枝有叶酸的琥珀酰肝素化肝素（H-PEG-F）连接到聚乙二醇上，制备了肝素-PEG-叶酸（H-PEG-F）。由于采用了共价策略，H-PEG-F 表现出两亲性，能够将疏水性药物（如紫杉醇）包埋在水溶液中形成肝素-PEG-叶酸-紫杉醇纳米粒（H-PEG-F-T NPs）。疏水性药物可以包埋在核内，而 H-PEG-F 缀合物可以通过暴露表面上的叶酸部分来稳定纳米粒。载体和纳米粒的结构已通过（1）H NMR 进行了表征，并且通过 UV 法定量分析了叶酸和紫杉醇的含量。通过场发射扫描电子显微镜（FESEM）和动态光散射（DLS）测量了 H-PEG-F-T NPs 的形态和尺寸。所有 NPs 均呈球形，尺寸均小于 200nm。随着 PEG 段长度的增加，NPs 的尺寸增加。通过流式细胞术方法，在各种条件下比较评估了细胞摄取的程度。细胞摄取的结果表明，对于 KB-3-1 细胞（叶酸受体过表达细胞系），载体和 NPs 的细胞摄取程度远远高于 A549 细胞（叶酸受体缺乏细胞系）；与 H-PEG-F 缀合物相比，H-PEG-F-T NPs 对 A549 细胞的摄取程度更大；当叶酸含量固定在相同值时，对于 KB-3-1 细胞，载体和 NPs 的细胞摄取程度随 PEG 链长的增加而增加。这表明叶酸受体介导的内吞作用和纳米粒的形成以及间隔物长度共同影响 H-PEG-F-T NPs 和 H-PEG-F 缀合物的细胞摄取效率。流式细胞术分析表明，用 H-PEG-F-T 处理的 KB-3-1 细胞被阻滞在细胞周期的 G2/M 期，这表明与紫杉醇具有相似的抑制机制。基于 H-PEG-F-T NPs 的形成的策略可潜在应用于各种治疗剂的癌细胞靶向递药。
